1. Field of the Invention
The present invention relates to a collimator which adjusts the shape of a region onto which radiation is directed and a control method thereof.
2. Description of the Related Art
An X-ray apparatus acquires an image within the body of an animal or a patient by irradiating the body with X-rays and then detecting X-rays that have passed through the body. Thereafter, the acquired image can be analyzed so as to enable detection of diseases within the body without an invasive procedure.
X-rays are electromagnetic waves having strong penetrating power which are discharged when electrons of a high speed collide with an object. An X-ray tube for generating X-rays generally includes a filament to discharge thermal electrons and electrodes to form a strong electric field in response to an applied high voltage. When a high voltage generated from a high voltage supply is applied to the X-ray tube, the filament forming a cathode discharges thermal electrons. The discharged thermal electrons drift under the influence of the applied high voltage so as to collide with an anode, and a spot having a local size on the anode where the thermal electrons collide, generates X-rays.
In general, an X-ray apparatus includes the above-described X-ray tube for generating X-rays, a collimator to adjust the shape of a region which the X-rays irradiate, and a detector to detect X-rays that have passed through an object.
The collimator to adjust the region which the X-rays irradiate blocks the radiated X-rays using a material which rapidly attenuates X-rays, such as tungsten, thus adjusting the shape of the irradiated region. The collimator typically also includes a structure to radiate visible light onto the same region as the region onto which the X-rays are radiated so as to enable a user to confirm the region onto which the invisible X-rays are radiated.